Re: [TUHS] V9 shell [was Re: Warner's Early Unix Presentation]

[Larry McVoy <lm@mcvoy.com>]

On Tue, Feb 11, 2020 at 11:24:25AM +0000, Ralph Corderoy wrote:
> > > Postel's principle: "be conservative in what you do, be liberal in
> > > what you accept from others" was doctrine in early HTML specs, and
> > > led to disastrous disagreement among browsers' interpretation of web
> > > pages. Sadly, the "principle" lives on despite its having been
> > > expunged from the HTML spec.
> 
> I often point to this Internet Draft when Postel's Law is brought up in
> modern discussions about letting standards slip.
> 
>     The Harmful Consequences of Postel's Maxim
>     M. Thomson, Mozilla, 2015-03-09
>     https://tools.ietf.org/html/draft-thomson-postel-was-wrong-00
> 
> After looking at divergence over time, and long-term costs, it suggests
> instead ???Protocol designs and implementations should be maximally
> strict???.  A shame it never became an RFC.
> 
> Arguing Postel's Law for accepting to deviate is easy as those arguing
> for strictness have to work out how the laxness could cause a problem.

Perhaps I'm being too kind, but I think people are being a little hard
on Jon.  I believe what he was pushing for was "it just works".  Anyone
who has been involved with a long lived software base knows that as you
roll out new versions you can break backwards compat.  Nobody likes it 
when you do that.